The face plate and the main body of a conventional clock are fastened together by a plurality of screws. The screws are capable of holding effectively the face plate and the main body; nevertheless they undermine the esthetic effect of the clock. The face plate and the main body of certain conventional clocks are fastened together by tenons and mortises in place of the screws. The tenons and the mortises can not hold the face plate and the main body of the conventional clock securely together in view of the fact that the tenons are easily disengaged with the mortises. In addition, the mortises are vulnerable to damage at the time when the tenons are forced into the mortises.